Reciprocating machine



Dec. 13, 1949 A. G. MALDON MICHELL 2,491,011

RECIPROGATING MACHINE 3 Sheets-Sheet 1 Filed Sept. 27, 1944 u f m r M m j J k i, m; G w M 7 E a Z A r y N 8 I a a 37 m l L I ll. 4 1 m a w fl /k 6 w m m F 1949 A. ca. MALDON MICHELL 2,491,011

RECIPROCATING MACHINE Filed Sept. 2'7, 1944 5 Sheets-Sheet 2 lNl/ENTOR I drlr/la/vy 050/705 MALpo/v Mmflgu ZWM/AM Dec. 13, 1949 A. G. MALDON MICHELL 2,491,011

RECIPROCATING MACHINE Filed Sept. 27, 1944 3 SheetsSheet- 3 XV FIG. 76

/A/ VEA/rOfi fl/vr/lom GEORGE Mama/1 .M/msu 5 V ZWM/WZ/Z Patented Dec. 13, 1949 RECIPROCATING MACHINE Anthony George Maldon.Miohell; .Melliourne,. Victoria, Australia Application September 27,1944; Serial No. 555,981 In Australia Octher.-30,.194'3 (c1; ace-21);

16' Claims.

invention relates to improvements in the reciprocatingmechanism of 'crankless machines,

such as ar described in; prior Patent No. 1,409.,- 057, and in similar machines in which reciprocating members require to be guided in their reciprocating movements and tobe supported against forces tending to displace them from their correct lines or reciprocation. Each reciprocating unitof such machines comprises one or more pistons reciprocating in a cylinder, or in coaxial cylinders and a yoke-member by which the |piS- ,axially to the opposite ends of the yoke.

The present improvements relate to the reciprocating elements themselves, especially to the yoke member, and also to the means employed for guiding the yoke in its reciprocating movement' and supporting it against forces tending to displace it from its true line of reciprocation.

An essential-feature ofthe invention is the provision of a fixed guide-member (hereinafter called trunk-member or simply trunk), having internal; and external bearing surfaces upon which the. yoke, or bearing elements attached thereto, slides or slide, and. having formed upon oneat least of. its ends a circumferential surface by which it is registered concentrically'with one of the cylinders so that its bearing surfaces. are parallel with the line of reciprocation of theyoke. A particular purpose of this feature of the invention is to provide trunk-members whose accurate alignment c-oaxially with the-axes of the .cylinders isbrought about automaticallyby the form given to the parts themselves-and does not require adjustment during, or after, their assembly. A-further particular object is to ensure, by the accuof'opposed coaxial cylinders, and shows a yoke racy of this alignment, that forces transmitted member and" a trunk member therefor con- 7 structed according to ithe'invention.

Figs. 2 and B are respectively a sectional side elevation and external plan view of the trunk member shown in Fig; 1.

Figs. 4 anddarerespe'ctivelya transverse crosssection and sideview, on. an enlarged, scale, of parts coacting with the trunkmember as shown min -=1 2m 3;

Fig. 6'. is. a longitudinal section, corresponding to Fig. l ,.of.,an.alte rnative construction.

Fig; 7. is. a crossesection of another optional c nstruction. ofjthe" trunk member and coacting bearingrnemberi Figs 8' and 9: show; in cross-section and side viewfrespectively, another construction alternaltijve'toi those shown in Figs. l'to 7, Fig. 8 being a section on line VIII+VIIIofFig 9;

Fig; 10 is a longitudinal section, corresponding to Figs., 1 and. 6, but on a larger scale, showing f'urtlieradaptatiorrs of the invention.

Figs. 11 aridlZi are detailed views on a larger scaleof'part's shown in Fig. 10, being respectively sections on lines XIfand XII'of that figure.

' Fig. 'l3illusatrates by'alongitudinal section an applrcationofthe' invention in which a single pistonis attached flexibly to the yoke-member.

Fig." l l is a parttransverse section on the lines XIV'Q Fi 3. I

Fig: 1:5," is atransverse' section, on an enlarged scale, on line XV of Figs. 13 and 16.

Fig..1 6isjan external' plan view, partly in section, rparts shown inFig. 1'5."

As, shown in" Figs, 1, 2"and 3', the reciprocating unit consists essentially of the yoke): and pistons 2, 3, the latterbeingrespectively attached to. connecting members (hereinafter called Shanks) l; 5, which may be integral with, or formed sepa rateiy and attachedto, the remainder of the yoke.

n r ng-members 5,1; 6a, 7a,,of known construction make actuating engagement between the reciprocating unit and the. rotating slant, or swash, latajtj nttachedto the yoke I, as by stud 9f, isalso afbearingmemberflil' (hereinafter cal1ed"rider) which makes sliding contact with the external surface ll of the trunk member [2, similarcontact'beihg. made with its inner surface 13 by the exterior. ofj'the. yoke itself. The trunk 12 hasthe form ofa hollow cylinder of which the outerand inner surfaces It, l3 are accurately coaxialiand" from themid'dle. portion of which an approximately semi-cylindrical portion, indicatedby' thedotted' lines. I2a,,Fig; 2, has been removed in orderto admitfthei peripheral portion q fihesl n fi; he radiall q pa t of 3 the wall of the trunk I2 a longitudinal slot I4 of uniform width is formed to admit part of the rider I and stud 9. Both the gap I2a and the slot I4 terminate short of the ends of the trunk I2, where its cylindrical form is complete, and at these ends it is fitted firmly within the mouths of the opposed coaxial cylinders I6, II, in which the pistons 2, 3 respectively reciprocate. The trunk I2 is thereby secured against displacement in any transverse direction. It is fixed longitudinally by being attached to one or both of the cylinders, as by screw I8, which however is to be regarded as a diagrammatic representation of other forms of fastening more suitable for the purpose, such as are described hereinafter with reference to Figs. 10, 11,12, 13 and 14 of the drawings. It is to be observed that a trunk-member of the form above described is conveniently adapted to be machined integrally from a cylindrical tube, such as one of the drawn tubes produced by steel manufacturers.

In Figs. 4 and 5 which show on a larger scale and in greater detail portions of the yoke I, rider II] and trunk I2 illustrated in Figs. 1 to 3, the rider I0 is shown as being formed with integral arms Illa, IIJb which make contact by portions I9a, I9b of their inner surfaces with the outer surface II of the trunk I2. The rider ID has also a central inward extension 23, through which passes the stud 9 by which it is attached to the yoke I, and which makes sliding contact with each of the faces of the slot I4, so as to prevent rotation of the yoke I with respect to the trunk I2 around their common axis. These bearing surfaces of the part 20, together with such portions of the outer surfaceof the yoke I as are required to make contact with the internal surface I3 of the trunk I2, may be lined with antifriction metal, sufiicient clearances being allowed in manufacture between the remainder of the mutually opposed surfaces to permit of this being done. Alternatively, in lieu of such linings of antifrictional metal, separate bearing-pads, or

slippers such as those hereinafter described as being fitted to the yoke shown in Figs. 13, 15, 16, may be used. In order to adjust the necessary working clearances between the opposed bearing surfaces suitable washers or shims 2| may be inserted between the rider ID and the yoke I. It is to be observed that a yoke-member of the form shown in Figs. 1, 4 and 5, and in other figures of the drawings, being substantially a portion of a solid cylinder, is adapted to be machined integrally from a solid cylindrical bar with a minimum of labour and cost.

In the modified form which is shown in Fig. 6 0f the trunk I2 described in connection with Figs. 1, 2 and 3, the gap, or portion actually or hypothetically removed from a complete hollow cylinder in order to form the trunk I2, is carried to the full length of the trunk at the end which is inserted into the cylinder I6, and at this end the trunk is held in contact with the cylinder on approximately one half only of the circumference, being secured thereto by the screw III.

The modified form of the trunk shown in Fig. 6 may be adopted to facilitate assembly, and for the same purpose in certain cases the end of the trunk may have the same form and mode of fixture at both of its ends as at the end which is shown in Fig. 6 as inserted in the cylinder IE, it then having an approximately semicylindrical form throughout its length.

In the alternative forms of the trunk IZA and rider IOA which are shown in Fig. '7, the trunk 4 I2, which otherwise may be similar to the trunks hereinbefore described with reference to Figs. 1 to 6, has formed on its exterior, adjacent to the slot I4, flat bearing surfaces 2Ia, 2 lb, which may preferably lie in a common plane. The rider IDA, which is attached to the yoke by stud 9, and has a part 28 fitting the slot I4 as hereinbefore described, is then formed with fiat bearing surfaces as shown making sliding contact with the surfaces 2Ia, 2Ib.

As illustrated in Figs. 8 and 9 the trunk I2B, which may otherwise be as in one or other of the hereinbefore described figures, is formed without a slot but, as an alternative thereto, is provided with a longitudinal bearing surface 22 on each of its sides.

The rider, 23, which is in the form of a saddle, is formed with arms 24, 24a, 25, 250., by which it is attached laterally to the yoke I, as by screws 26, and makes sliding contact by its cylindrical portion 2! with the outer cylindrical surface of the trunk I23 and also by the inner surfaces of its arms 24, 24a with the bearing surfaces 22 of the trunk. These parts of the rider 23 which make contact with the trunk may be lined with anti-friction metal as indicated. Sliding contact is made between the exterior surface of the yoke I and the inner cylindrical surface I3 of the trunk in the same way as hereinbefore described wi h reference to other figures.

Figs. 10, 11 and 12 illustrate a reciprocating unit and trunk applied in accordance with the invention to a pair of opposed cylinders which respectively have, in the case of the cylinder I6 a set of oil-retention rings 30 fitting the shank 4, and in the case of the cylinder I! a conventional type of packing 3i fitting the shank 5, the rings 33 and packing 3| being respectively contained in'the cylindrical bosses 32, 33, of the fianged members 3 35, which cover the mouths of the respective cylinders, and which may be divided diametrally in halves to facilitate assembly. The member 34 has also a cylindrical boss 36 on the side towards the yoke I. The boss 32 fits firmly in the mouth of the cylinder I6 which is bored truly concentric with the cylinder walls, and the bosses 32 and 36 are accurately co-axial. The fiange 31 of the member 35 is formed with a cylindrical recess whose edge 38 fits firmly upon the external surface of the projecting mouth of the cylinder [1, this surface being formed accurately concentric with the cylinder wall. The edge 38 and external surface of the boss 33 are also accurately co-axial.

The trunk I2C, with which the reciprocating unit makes sliding contact by means of the yoke I and rider IE3, the latter being constructed as hereinbefore described with reference to Figs. 4,

' 5 and 6, except that it is attached to the yoke by two studs 9, 9, instead of one only, or by alternative means, as hereinbefore explained, is semi-cylindrical, its internal surface I3 being of the same radius as each of the bosses 33 and 36. Accordingly, when the internal surface I3 of the trunk I2C is brought closely into contact with these bosses, the guide becomes truly co-axial with the cylinders I6 and II. This contact is shown in Fig. 11 as being effected, in the case of the boss 36 by forming at the corresponding end of the trunk I2C an axial, conically-tapered, rim 3!! extending around the semi-circumference. Fitted to this conical rim is a segmental clamp 49, Figs. 10 and 11, studs 4| adapted to draw this clamp over the tapered rim 39 being studded into the end wall of the cylinder I6, these studs also,

as shown, supplementing. other studs 4.2a. in Stcuringthe. flange. of the member 35 to the cylinder wall. It will be -.seen.that,when. th stud 4;]; arev tightened, the. end of the trunk I2 is by this. means fixed both longitudinally and coaxially with respect to the cylinder I6.

At the other end of the trunk 120 different means forits location are illustrated:

Its. external and internal cylindrical: surfaces H and i3 being continued to its. end, and theexterior surface of the boss 3.3 of the member 35 beingv made of the same radius as the internal surface it. of the trunk, a short semi-cylindrical fillingpiece 42, having the same. internal. and externalv radii as the trunk is clamped together withthe end of the trunk by thebracelet or clamp d3, this being. formed in two halves. and drawn together by bolts 44, as shown in Fig. 12. The length ofthe trunk IZC is preferablyso designed in relation to the dimensions of the frame and other parts of the machine that the cylindrical end of the trunk remains clear of the face of the part 31 to a sufficient extent to prevent contact taking place between them during all movements, due to changes of temperature or other causes, to which the machine may be subjected. It will be seen that the method of fixation of-this end of the trunk IZC, which has just been described, ensures its being secured coaxially with the cylinder H while allowing the desirable, small, longitudinal movement.

In all the applications of the invention hereinbefore described, the reciprocating member is shown as comprising two pistons attached to opposite ends of the yoke and operating in opposed coaxial cylinders. In each case, however, if a reciprocating unit with one; piston only is required, any of the constructions described may be used, one of the pistons and; the shank attaching it to the yoke being omitted together with the corresponding cylinder, provided-- that means equivalent to the inwardly projecting mouth of the omitted cylinder are used to support the trunkiat that end coaxiallywith the cylinder at the other end.

In the construction now aboutto be described with reference toFigs. 13 to 16 of the drawings, the reciprocating unit and trunk-are particularly designed for use with a; single piston and the trunk is supported only from one end, viz. that end at which the piston islocated. This piston furthermore is shown as being furnished with a piston-rod 45 by means of which it is attached a) the yoke, though alternatively it may be attachedto a shank forming part of, the yoke, as hereinbefore described, without otherwise modifying the construction. In Fig. 13 the attachment is shown as being effected by forming a spherical end 59 on the yoke l, and a spherical flange 55 of uniform thickness on the matching end of the rod 45, together with a cap-piece 52 fitting the back of the flange 5i and attached to the yoke I by screws 53 which pass loosely through holes in the flange 5|. At its other end the rod- 45 may be attached to the piston 3 by means of a flange as 54 into which the rod 45 is screwed and which may be either-bolted rigidly to the. piston as shown, orattached to it in the same way as the flange 5| tothe yoke. The cylinder [1, in which the piston 3 reciprocates, is formed by means of a liner 55 of circumferentially uniform thickness fitted into theframe 56 of the machine in the usual manner, being secured lon gitudinally in the frame by the spring-ring 51.

" The trunk [2D, which has external and internal surfaces H and" I3; andslot M: as hereinbfore described, isprovided; with a circumferential rim 58 near its end towardsthe cylinderand: is finished between the. rim; 58: andits end= to.a-cylindrical form truly coaxial with the. surfaces: l1 and I 3 and of. such diameter as. tofit. firmly. in the mouth of the liner 55.

The face of the rim 58. remote from the. cylinder is preferably. spherically. convex inform as shown. Over the rim 58 is fitted a ring.59.which has a corresponding concave spherical. internal face and which is attached to the frame 56.:ofathe machine. by studs Bil, the dimensionsof: the parts being so arranged that when the studs Gila-re fully tightened up, the ring 59. is firmly pressed against the rim 58 and the latter. against the end of the liner 55. before the ring 59.comes:into contact with the frame 55. twill be seen that by this means the trunk MD. is fixed. both longitudinally and coaxially with respect tosthe. cylinder H. In certain cases, especially inmachines of small size, the trunk i2D may be formed-integrally with the liner 55:.as a single. unit. The spring-ring 5?, ring 59. and studs 66 then. serve solely to secure the combined trunk and liner to the frame of the machine. Alternativelyto the complete ring 59 two or more segmental. clamps, similar to the clamp lflhereinbefore described in connection with Figs. wand 11', may be. fitted around the rim 58 to hold the trunk i213 incontact with liner 55.

The construction of the yoke i anditscoaction with the trunk MD are substantially the same as in the constructions. h'ereinbefore described especially those illustrated in Figs. 4.1 and 5. As a further modification, however, desirable where particularly accurate. and eificient; guidance of the yoke is required, and in case's-whenit is desired to exempt the pistons when-rigidly attached to the yoke from all lateral; forcesthe yoke is fitted with special bearingslippers Blon both of its ends and on both of-its. sides (see especially Figs. 15 and 16), these slippers projecting slightly above the surface of the yoke itself and alone making sliding contact with the internal surface 13 of the. trunk IED.

The faces of the slippers 6| which makecontact with the surface 13 are of cylindrical form fitting the latter. The remainderof the surface of each slipper is of spherical form accurately fitting spherical recesses formed in the yoke l. The slippers are retained in these recesses by pins 62, which preferably pass loosely through holes in the slippers. Similar slippers 63- bearing on the external surface H of the trunk i213 are fitted in the rider If! which is formed, andattached to the yoke I by studs 9; 9, each as described in connection with Figs. 4 and 5, or: Fig. 1!), the clearances between the slippers 6!, 53 and the trunk I2D being regulated by suitable wash.- ers or shims 64 inserted between the enlarged portion, 55, of the stud-and therider [6-, as indicated in Fig. 15.

As a further modification, inplace of the extension 25 of the rider it, which is shown in Figs. 4 and '7 as beingprovided for-preventing rotation of the yoke i about its axis, a slipperblock 65 is fitted loosely on the enlargedpar't 65 of each of the studs, 9, 9, these blocks'sliding in the slot 14.

In order to lubricate effectively the -surfaces H, [3, the slippers 6!, B3,- and the blocks 65, 66, oil is caused to fiow, as froman oil-pump, into the slot it from a pipe 51. and nozzletd'mounted preferably on theouter end" ofthe trunk- [21).

7 Recesses 68 may be formed in the yoke I as shown in Figs. 13, 15, 16, to assist in the distribution of the oil to the parts to be lubricated.

Various modifications in construction, mode of operation, method and use of an invention may and do occur to others, especially after benefiting from knowledge of such a disclosure as that herein presented of the principles involved, but the invention itself is not confined to the present showing.

I claim:

1. In a mechanism comprising a cylinder, a piston working in the cylinder and a reciprocating unit of which the piston forms part, a guide comprising a trunk member having internal and external longitudinal bearing surfaces at least one of which is cylindrical adapted to make sliding contact with corresponding surfaces provided on said reciprocating unit.

2. In a mechanism comprising a cylinder, a piston working in the cylinder and a reciprocating unit of which the piston forms part, a guide comprising a trunk-member fixed coaxially with respect to said cylinder and having internal and external bearing surfaces at least one of which is cylindrical adapted to make sliding contact With corresponding surfaces provided on members forming parts of said reciprocating unit.

3'. In a mechanism comprising a cylinder, a piston working in the cylinder and a reciprocating unit of which the piston forms part, a guide comprising a trunk-member fixed coaxially with respect to said cylinder and having formed upon it an internal cylindrical bearing surface, an external cylindrical bearing surface and at least one longitudinal bearing surface transverse to said cylindrical surfaces, all said bearing surfaces being adapted to make sliding contact with corresponding surfaces provided on members forming parts of said reciprocating unit.

4. In a mechanism comprising a cylinder, a piston working in said cylinder and a reciprocating unit of which the piston forms part, a guide comprising a trunk-member having formed upon it internal, external and substantially radial bearing-surfaces, members forming parts of the reciprocating unit and severally provided with bearing surfaces adapted to make sliding contact with said internal, external and radial bearing surfaces and means for fixing said trunk-member coaxially with respect to said cylinder.

5. In a mechanism according to claim 1, the trunk member having formed on one of its ends a circumferential surface by means of which it is registered coaxially with the cylinder so that its longitudinal bearing surfaces are parallel with the line of reciprocation of the reciprocating unit.

6. In a mechanism comprising a cylinder, a piston working in the cylinder and a reciprocating unit of which the piston forms a part, a guide comprising a trunk-member having formed on one of its ends a cylindrical surface by means of which it is registered coaxially with the cylinder and means for fixing said trunk-member relatively to the cylinder in the longitudinal direction.

7. In a mechanism according to claim 6, in which the means for fixing the trunk-member relatively to the cylinder in the longitudinal direction comprises a spherical surface transverse to said cylindrical surface.

8. In a mechanism comprising a cylinder, a piston working in the cylinder and a reciprocating unit of whichthe piston forms a part, a guide comprising a trunk-member of which the part by which sliding contact is made with the reciprocating unit is substantially a portion of a hollow cylinder and the internal and external longitudinal bearing surfaces are portions of circular cylinders coaxial with one another and with the cylinder in which the piston works.

9. In a mechanism according to claim 4, a part of the trunk-member by which sliding contact is made with the reciprocating unit being substantially a portion of a hollow cylinder, with concentric external and internal longitudinal bearing surfaces, and the radial bearing surfaces, being the bounding surfaces of a slot formed longitudinally in the wall of said hollow cylinder.

10. In a mechanism comprising a pair of coaxial cylinders, pistons working in the cylinders and a reciprocating unit of which the pistons are parts, a guide comprising a trunk-member extending between the cylinders and having internal and external bearing surfaces adapted to make sliding contact with corresponding surfaces on said reciprocating unit, a circumferential cylindrical surface on each of its ends by means of which it is registered coaxially with the cylinder at that end, and means by which the said trunk-member is fixed relatively to one at least of said cylinders in the longitudinal direction.

11. In a mechanism comprising a cylinder, a piston working in the cylinder and a reciprocating unit of which the piston forms a part, a guide comprising a trunk-member, said trunk-member being substantially a portion of a hollow cylinder adapted to be formed integrally from a hollow tube.

12. In a mechanism comprising a cylinder, a piston working in the cylinder and a reciprocating unit of which the piston forms a part, a guide comprising a trunk-member, said reciprocating unit comprising a yoke-member having a bearing surface adapted to make sliding contact with the internal longitudinal bearing surface of the trunk-member and a rider having a bearing surface adapted to make sliding contact with the external longitudinal surface of the trunkmember.

13. In a mechanism comprising a cylinder, a piston working in the cylinder and a reciprocating unit of which the piston forms a part, a guide comprising a trunk-member having formed upon it internal, external, longitudinal substantially cylindrical bearing surfaces and substantially radial bearing surfaces, said reciprocating unit comprising a yoke-member having a bearing surface adapted to make sliding contact with the internal longitudinal bearing surface of the trunk-member, a rider-member having a bearing surface adapted to make sliding contact with the external longitudinal surface of the trunk-member and a member adapted to make sliding contact with the substantially radial surface or surfaces of the trunk-member.

14. In a mechanism comprising a cylinder, 2, piston working in the cylinder and a reciprocating unit of which the piston forms a part, a guide comprising a trunk-member having an internal substantially cylindrical longitudinal bearing surface, a yoke-member forming part of the reciprocating unit and having substantially the form of a portion of a solid cylinder adapted to make sliding contact by its periphery with said cylindrical surface of the trunk-member and to be formed integrally from a cylindrical bar.

, l5. In a mechanism comprising a pair of coaxial cylinders, a hollow trunk member interposed between said cylinders, a piston in each of the cylinders, a yoke interconnecting the pistons, said trunk member having circumferential endportions fitting into the cylinders and affixed to at least one of the cylinders and having an inner cylindrical longitudinal bearing surface coaxial with the cylinders, and a cylindrical surface on the yoke in slidable engagement with said bearing surface.

16. In a mechanism comprising a pair of coaxial cylinders, a hollow trunk member interposed between said cylinders, a yoke interconnecting the pistons, said trunk member having circumferential end-portions fitting into the cylinders and afiixed to at least one of the cylinders and having an inner cylindrical longitudinal bearing surface coaxial with the cylinders, a cylindrical surface on the yoke in slidable engagement with said bearing surface, and means for preventing relative rotation between the yoke and the trunk member.

ANTHONY GEORGE MALDON MICHELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

